Impact of the COVID-19 pandemic on tuberculosis management in Spain.

BACKGROUND: The impact of COVID-19 on the diagnosis and management of tuberculosis (TB) patients is unknown. METHODS: Participating centres completed a structured web-based survey regarding changes to TB patient management during the COVID-19 pandemic. The study also included data from participating centres on patients aged ≥18 diagnosed with TB in 2 periods: March 15 to June 30, 2020 and March 15 to June 30, 2019. Clinical variables and information about patient household contacts were retrospectively collected. RESULTS: A total of 7 (70%) TB units reported changes in their usual TB team operations. Across both periods of study, 169 patients were diagnosed with active TB (90 in 2019, 79 in 2020). Patients diagnosed in 2020 showed more frequent bilateral lesions in chest X-ray than patients diagnosed in 2019 (P = 0.004). There was a higher percentage of latent TB infection and active TB among children in households of patients diagnosed in 2020, compared with 2019 (P = 0.001). CONCLUSIONS: The COVID-19 pandemic has caused substantial changes in TB care. TB patients diagnosed during the COVID-19 pandemic showed more extended pulmonary forms. The increase in latent TB infection and active TB in children of patient households could reflect increased household transmission due to anti-COVID-19 measures.

Epidemiology of Non-Tuberculous Mycobacteria isolated from clinical specimens in Madrid, Spain, from 2013 to 2017.

The epidemiology of non-tuberculous mycobacteria (NTM) in Spain is largely unknown because systematic reporting is not compulsory. The aim of our study was to describe the frequency and diversity of NTM species in our region and their distribution according to the source sample, gender, and age of the patients. We performed a multicenter study of all NTM isolated in 24 public hospitals in Madrid from 2013 to 2017. A total of 6.923 mycobacteria were isolated: 4535 (65.5%) NTM, and 2.388 (34.5%) Mycobacterium tuberculosis complex (MTB). Overall, 61 different NTM species were identified. The most frequently isolated species were Mycobacterium avium complex (47.7%), M. lentiflavum (12.2%), M. gordonae (9.2%), M. fortuitum (8.9%), and M. abscessus (3.9%). Whereas MTB cases were stable during the study period, the number of NTM isolates increased considerably from 930 isolates in 2013 to 1012 in 2017; a sharp increase occurred in the last year. The rise in NTM isolates was mostly due to M. lentiflavum, M. kansasii, and M. abscessus mainly isolated from respiratory specimens in patients older than 60. The increase in isolation rate of NTM in our region is consistent with the increasing rates reported worldwide in the last decades. The rise in NTM isolates was mainly attributed to M. lentiflavum but it also should be noted the increasing of species with high pathogenic potential such as M. kansasii and M. abscessus.

A simple device for headspace sorptive extraction prior to gas chromatography-mass spectrometry analysis.

A device for headspace sorptive extraction (HSSE) combined with gas chromatography separation and mass spectrometry detection (GC-MS) is presented. The gadget is based on a simple magnetic disk that permits the stir bar to be placed at the top of the sample vial. The complete surface of the coated stir bar is exposed to the headspace atmosphere, and the movement of the bar caused by the magnetic stirrer in the liquid sample facilitates the sorption process. The final consequence is increased sensitivity and repeatability when compared with a glass-made comercial device for the same purpose. Successful determination of ten chlorobenzenes in waters testifies the good performance of the new device.

Incidencia de nefropatía por contraste en pacientes sometidos a tomografía computarizada: ¿qué factores la condicionan? / Factors affecting the incidence of contrast-induced nephropathy in patients undergoing computed tomography

Objetivo: Analizar la incidencia de nefropatía por contraste en una cohorte de pacientes sometidos a tomografía computarizada (TC) con contraste yodado intravenoso. Valorar los resultados de la nefroprotección con N-acetilcisteína. Pacientes y métodos: Estudio observacional prospectivo, entre los meses de marzo y julio de 2016. Los pacientes seleccionados tenían programada una TC. Se incluyeron los primeros 5 pacientes de cada día, que aceptaban participar y firmaban el consentimiento informado. Se registraron antecedentes cardiovasculares, tratamientos crónicos e indicación de la TC. Se determinó la creatinina y la urea en sangre pre-TC y pos-TC. El filtrado glomerular se determinó por MDRD-4 (Modification of Diet in Renal Disease). Respecto al contraste, se analizó tipo y dosis. Se registró el uso de N-acetilcisteína anterior a la TC. Estadística: SPSS 15.0(R) utilizando comparación de medias y proporciones. Significación: p < 0,05. Resultados: No se detectó ninguna NC en 202 pacientes estudiados. Datos globales: edad: 63,92 ± 12 años (rango 22-87); 57,4% varones; 21,8% diabéticos; 39,6% hipertensos; 176 pacientes tenían MDRD4 ≥ 60 ml/min/1,73 m2 (89,45 ± 14, rango 62,36-134,14) y 26 MDRD4 < 60 ml/min/1,73 m2 (45,38 ± 11, rango 9,16-58,90). La principal indicación de TC fue oncológica (81,2%). El único contraste administrado fue iopamidol, en dosis de 107,83 ± 11 ml (rango 70-140). El intervalo de días entre analíticas fue de 4,06 ± 1 días. Solo en 13 pacientes se administró N-acetilcisteína: en 9 con MDRD < 60 ml/min/1,73 m2 y en 4 con MDRD4 > 60 ml/min/1,73 m2 (p = 0,000). Conclusiones: La incidencia de NC es no significativa en la cohorte estudiada con un filtrado glomerular superior a 30 ml/min/1,73 m2: la realización de TC de forma "programada", utilizando un contraste yodado "no iónico" en dosis relativamente baja, es un factor que quizás explique estos resultados favorables

Objective: To analyze the incidence of contrast-induced nephropathy in a cohort of patients undergoing computed tomography (CT) with intravenous iodinated contrast material. To evaluate the efficacy of N-acetylcysteine in preventing contrast-induced nephropathy. Patients and methods: This prospective observational study was carried out in the months comprising March 2016 through July 2016. We selected the first five patients scheduled to undergo CT examination each day who agreed to participate and signed the informed consent form. We recorded patients' cardiovascular histories, chronic treatments, and indications for the CT examination. We measured blood levels of creatinine and urea before and after the CT examination. We used the Modification of Diet in Renal Disease (MDRD-4) equation to estimate the glomerular filtration rate. We analyzed the type and dose of contrast material. We recorded whether N-acetylcysteine was administered before the CT examination. We used SPSS 15.0(R) to compare means and proportions. Statistical significance was set at p < 0.05. Results: No incidents of contrast-induced nephropathy were detected in any of the 202 patients included [mean age, 63.92 ± 12 years (range 22-87); 57.4% male; 21.8% diabetic; 39.6% hypertensive; 87.1% had MDRD4 ≥ 60 ml/min/1.73 m2 (89.45 ± 14, range 62.36-134.14) and 12.9% had MDRD4 < 60 ml/min/1.73 m2 (45.38 ± 11, range 9.16-58.90)]. The most common indication for CT examinations was oncologic (81.2%). The only contrast agent administered was iopamidol; the mean dose was 107.83 ± 11 ml (range 70-140). The mean interval between pre-CT and post-CT laboratory tests was 4.06 ± 1 days. Only 13 patients received N-acetylcysteine; 9 of these had MDRD < 60 ml/min/1.73 m2 and 4 had MDRD4 ≥ 60 ml/min/1.73 m2 (p = 0.000). Conclusions: The incidence of contrast-induced nephropathy was not significant in patients with glomerular filtration rates greater than 30 ml/min/1.73 m2: these favorable results might be due to analyzing only scheduled examinations and to using relatively low doses of a "nonionic" iodinated contrast agent

Factors affecting the incidence of contrast-induced nephropathy in patients undergoing computed tomography. / Incidencia de nefropatía por contraste en pacientes sometidos a tomografía computarizada: ¿qué factores la condicionan?

OBJECTIVE: To analyze the incidence of contrast-induced nephropathy in a cohort of patients undergoing computed tomography (CT) with intravenous iodinated contrast material. To evaluate the efficacy of N-acetylcysteine in preventing contrast-induced nephropathy. PATIENTS AND METHODS: This prospective observational study was carried out in the months comprising March 2016 through July 2016. We selected the first five patients scheduled to undergo CT examination each day who agreed to participate and signed the informed consent form. We recorded patients' cardiovascular histories, chronic treatments, and indications for the CT examination. We measured blood levels of creatinine and urea before and after the CT examination. We used the Modification of Diet in Renal Disease (MDRD-4) equation to estimate the glomerular filtration rate. We analyzed the type and dose of contrast material. We recorded whether N-acetylcysteine was administered before the CT examination. We used SPSS 15.0® to compare means and proportions. Statistical significance was set at p < 0.05. RESULTS: No incidents of contrast-induced nephropathy were detected in any of the 202 patients included [mean age, 63.92 ± 12 years (range 22-87); 57.4% male; 21.8% diabetic; 39.6% hypertensive; 87.1% had MDRD4 ≥ 60 ml/min/1.73 m2 (89.45 ± 14, range 62.36-134.14) and 12.9% had MDRD4 < 60 ml/min/1.73 m2 (45.38 ± 11, range 9.16-58.90)]. The most common indication for CT examinations was oncologic (81.2%). The only contrast agent administered was iopamidol; the mean dose was 107.83 ± 11 ml (range 70-140). The mean interval between pre-CT and post-CT laboratory tests was 4.06 ± 1 days. Only 13 patients received N-acetylcysteine; 9 of these had MDRD < 60 ml/min/1.73 m2 and 4 had MDRD4 ≥ 60 ml/min/1.73 m2 (p = 0.000). CONCLUSIONS: The incidence of contrast-induced nephropathy was not significant in patients with glomerular filtration rates greater than 30 ml/min/1.73 m2: these favorable results might be due to analyzing only scheduled examinations and to using relatively low doses of a "nonionic" iodinated contrast agent.

In situ ionic liquid dispersive liquid-liquid microextraction coupled to gas chromatography-mass spectrometry for the determination of organophosphorus pesticides.

Nine organophosphorus pesticides (OPPs) were determined in environmental waters from different origins using in situ ionic liquid dispersive liquid microextraction (IL-DLLME). This preconcentration technique was coupled to gas chromatography-mass spectrometry (GC-MS) using microvial insert thermal desorption, an approach that uses a thermal desorption injector as sample introduction system. The parameters affecting both the microextraction and sample injection steps were optimized. The proposed method showed good precision, with RSD values ranging from 4.1 to 9.7%, accuracy with recoveries in the 85-118% range, and sensitivity with DLs ranging from 5 to 16 ng L-1.

Direct sample introduction-gas chromatography-mass spectrometry for the determination of haloanisole compounds in cork stoppers.

A solventless analytical method is proposed for analyzing the compounds responsible for cork taint in cork stoppers. Direct sample introduction (DSI) is evaluated as a sample introduction system for the gas chromatography-mass spectrometry (GC-MS) determination of four haloanisoles (HAs) in cork samples. Several parameters affecting the DSI step, including desorption temperature and time, gas flow rate and other focusing parameters, were optimized using univariate and multivariate approaches. The proposed method shows high sensitivity and minimises sample handling, with detection limits of 1.6-2.6ngg-1, depending on the compound. The suitability of the optimized procedure as a screening method was evaluated by obtaining decision limits (CCα) and detection capabilities (CCß) for each analyte, which were found to be in 6.9-11.8 and 8.7-14.8ngg-1, respectively, depending on the compound. Twenty-four cork samples were analysed, and 2,4,6-trichloroanisole was found in four of them at levels between 12.6 and 53ngg-1.

Cloud point extraction and gas chromatography with direct microvial insert thermal desorption for the determination of haloanisoles in alcoholic beverages.

A sensitive analytical procedure for the determination of four haloanisoles (2,4,6 trichloroanisole, 2,4,6-tribromoanisole, 2,3,4,6-tetrachloroanisole and pentachloroanisole) related with cork taint defects in wines, in different types of alcoholic beverages has been developed. The analytes were extracted from the matrix samples by cloud point extraction (CPE) using Triton X-114 heated to 75°C, and the surfactant rich phase was separated by centrifugation. By means of direct microvial insert thermal desorption, 20µL of the CPE obtained extract was submitted to gas chromatography-mass spectrometry (GC-MS) analysis. The parameters affecting the CPE and microvial insert thermal desorption were optimized. Quantification was carried by matrix-matched calibration using an internal standard. Detection limits ranged between 12.9 and 20.8ngL(-1), depending on the compound, for beer and wine samples, whereas for whiskies values in the 46.3-48ngL(-1) range were obtained, since these samples were diluted for analysis. Recoveries for alcoholic beverages were in the 89-111% range, depending on the analyte and the sample.

Dispersive liquid-liquid microextraction for the determination of nitrophenols in soils by microvial insert large volume injection-gas chromatography-mass spectrometry.

A rapid and sensitive procedure for the determination of six NPs in soils by gas chromatography and mass spectrometry (GC-MS) is proposed. Ultrasound assisted extraction (UAE) is used for NP extraction from soil matrices to an organic solvent, while the environmentally friendly technique dispersive liquid-liquid microextraction (DLLME) is used for the preconcentration of the resulting UAE extracts. NPs were derivatized by applying an "in-situ" acetylation procedure, before being injected into the GC-MS system using microvial insert large volume injection (LVI). Several parameters affecting UAE, DLLME, derivatization and injection steps were investigated. The optimized procedure provided recoveries of 86-111% from spiked samples. Precision values of the procedure (expressed as relative standard deviation, RSD) lower than 12%, and limits of quantification ranging from 1.3 to 2.6ngg(-1), depending on the compound, were obtained. Twenty soil samples, obtained from military, industrial and agricultural areas, were analyzed by the proposed method. Two of the analytes were quantified in two of the samples obtained from industrial areas, at concentrations in the 4.8-9.6ngg(-1) range.

Aplicación práctica de los test cognitivos breves / Practical application of brief cognitive tests

Introducción: Los test cognitivos breves (TCB) pueden ayudar a detectar el deterioro cognitivo (DC) en el ámbito asistencial. Se han desarrollado y/o validado varios TCB en nuestro país, pero no existen recomendaciones específicas para su uso. Desarrollo: Revisión de estudios sobre el rendimiento diagnóstico en la detección del DC llevados a cabo en España con TCB que requieran menos de 20 min y recomendaciones de uso consensuadas por expertos, sobre la base de las características de los TCB y de los estudios disponibles. Conclusión: El Fototest, el Memory Impairment Screen (MIS) y el Mini-Mental State Examination (MMSE) son las opciones más recomendables para el primer nivel asistencial, pudiendo añadirse otros test (Test del Reloj [TR] y test de fluidez verbal [TFV]) en caso de resultado negativo y queja o sospecha persistente (aproximación escalonada). En el segundo nivel asistencial es conveniente una evaluación sistemática de las distintas áreas cognitivas, que puede llevarse a cabo con instrumentos como el Montreal Cognitive Assessment, el MMSE, el Rowland Universal Dementia Assessment o el Addenbrooke's Cognitive Examination, o bien mediante el uso escalonado o combinado de herramientas más simples (TR, TFV, Fototest, MIS, Test de Alteración de la Memoria y Eurotest). El uso asociado de cuestionarios cumplimentados por un informador (CCI) aporta valor añadido a los TCB en la detección del DC. La elección de los instrumentos vendrá condicionada por las características del paciente, la experiencia del clínico y el tiempo disponible. Los TCB y los CCI deben reforzar -pero nunca suplantar- el juicio clínico, la comunicación con el paciente y el diálogo interprofesional

Introduction: Brief cognitive tests (BCT) may help detect cognitive impairment (CI) in the clinical setting. Several BCT have been developed and/or validated in our country, but we lack specific recommendations for use. Development: Review of studies on the diagnostic accuracy of BCT for CI, using studies conducted in Spain with BCT which take less than 20 min. We provide recommendations of use based on expert consensus and established on the basis of BCT characteristics and study results. Conclusion: The Fototest, the Memory Impairment Screen (MIS) and the Mini-Mental State Examination (MMSE) are the preferred options in primary care; other BCT (Clock Drawing Test [CDT], test of verbal fluency [TVF]) may also be administered in cases of negative results with persistent suspected CI or concern (stepwise approach). In the specialised care setting, a systematic assessment of the different cognitive domains should be conducted using the Montreal Cognitive Assessment, the MMSE, the Rowland Universal Dementia Assessment, the Addenbrooke's Cognitive Examination, or by means of a stepwise or combined approach involving more simple tests (CDT, TVF, Fototest, MIS, Memory Alteration Test, Eurotest). Associating an informant questionnaire (IQ) with the BCT is superior to the BCT alone for the detection of CI. The choice of instruments will depend on the patient's characteristics, the clinician's experience, and available time. The BCT and IQ must reinforce - but never substitute - clinical judgment, patient-doctor communication, and inter-professional dialogue

Practical application of brief cognitive tests.

INTRODUCTION: Brief cognitive tests (BCT) may help detect cognitive impairment (CI) in the clinical setting. Several BCT have been developed and/or validated in our country, but we lack specific recommendations for use. DEVELOPMENT: Review of studies on the diagnostic accuracy of BCT for CI, using studies conducted in Spain with BCT which take less than 20 min. We provide recommendations of use based on expert consensus and established on the basis of BCT characteristics and study results. CONCLUSION: The Fototest, the Memory Impairment Screen (MIS) and the Mini-Mental State Examination (MMSE) are the preferred options in primary care; other BCT (Clock Drawing Test [CDT], test of verbal fluency [TVF]) may also be administered in cases of negative results with persistent suspected CI or concern (stepwise approach). In the specialised care setting, a systematic assessment of the different cognitive domains should be conducted using the Montreal Cognitive Assessment, the MMSE, the Rowland Universal Dementia Assessment, the Addenbrooke's Cognitive Examination, or by means of a stepwise or combined approach involving more simple tests (CDT, TVF, Fototest, MIS, Memory Alteration Test, Eurotest). Associating an informant questionnaire (IQ) with the BCT is superior to the BCT alone for the detection of CI. The choice of instruments will depend on the patient's characteristics, the clinician's experience, and available time. The BCT and IQ must reinforce - but never substitute - clinical judgment, patient-doctor communication, and inter-professional dialogue.

Evaluation of three headspace sorptive extraction coatings for the determination of volatile terpenes in honey using gas chromatography-mass spectrometry.

Headspace sorptive extraction (HSSE) was used to preconcentrate seven monoterpenes (eucalyptol, linalool, menthol, geraniol, carvacrol, thymol and eugenol) for separation by gas chromatography and mass spectrometry (GC-MS). Three commercially available coatings for the stir bars, namely Polydimethylsiloxane (PDMS), polyacrilate (PA) and Ethylene glycol-silicone (EG-Silicone), were tested, and the influential parameters both in the adsorption and the thermal desorption steps were optimized. PDMS provided the best sensitivity for linalool, geraniol, menthol and eucalyptol, whereas EG-Silicone was best for extracting the phenolic monoterpenes studied. Considering the average obtained slopes from all compounds, PDMS pointed as the best option, and the analytical characteristics for the HSSE-TD-GC-MS method using this coating were obtained. Quantification of the samples was carried out by matrix-matched calibration using a synthetic honey. Detection limits ranged between 0.007 and 0.032 ng g(-1), depending on the compound. Twelve honey samples of different floral origins were analyzed using the HSSE-GC-MS method, the analytes being detected at concentrations up to 64 ng g(-1).

Direct sample introduction gas chromatography and mass spectrometry for the determination of phthalate esters in cleaning products.

A method using direct sample introduction (DSI) coupled to gas chromatography-mass spectrometry (GC-MS) is developed for the determination of six phthalate esters (dimethyl, diethyl, dibutyl, butylbenzyl, diethylhexyl and dioctyl phthalate) in cleaning products. The different variables involved in the DSI step, including venting time and temperature, vaporisation time and temperature, injector heating temperature and gas flow rate and pressure, were evaluated and optimised using Taguchi orthogonal arrays. The proposed method, using calibration against methanolic standards, showed good linearity in the 0.05-15 µg g(-1) range and good repeatability, with RSD values ranging from 3.5% to 5.7%. Quantification limits between 0.010 and 0.041 µg g(-1), depending on the compound, were attained, while recovery assays provided values from 83% to 115%. Twenty-seven cleaning products were analysed using the DSI-GC-MS method, being four phthalates (dimethyl, diethyl, dibutyl and diethylhexyl phthalate) found in fourteen of them at concentration levels in the 0.1-21 µg g(-1) range. Compared with the most common GC injection technique, which uses the split/splitless injector, the proposed DSI procedure provided larger peak areas and lower detection limits, as result of the greater injected volume and reduction in noise.

Betalactamasas de espectro extendido en las infecciones del tracto urinario causadas por enterobacterias: aproximación a su conocimiento y pautas de actuación / Extended-spectrum beta-lactamases in urinary tract infections caused by Enterobacteria: Understanding and guidelines for action

Contexto: Las betalactamasas son enzimas bacterianas que protegen a los microorganismos de los efectos letales de los antibióticos β-lactámicos. Su producción es el mecanismo más importante de resistencia a estos antibióticos, especialmente en bacterias gramnegativas. Objetivo: Revisar la magnitud del problema de las betalactamasas de espectro extendido (BLEE) en el ámbito urológico y presentar las pautas de actuación fundamentales al respecto, los principales factores de riesgo y las estrategias de prevención. Adquisición de evidencia: Se lleva a cabo una estrategia de búsqueda estructurada tipo paciente, problema, intervención, comparación y resultado en PubMed-Medline identificando los estudios más relevantes relacionados con el manejo de pacientes con infección urinaria por microorganismos productores de BLEE. Se presenta también análisis de la casuística de nuestro centro en esta misma problemática. íntesis de evidencia: Las BLEE se encuentran en enterobacterias, fundamentalmente Klebsiella sp. y Escherichia coli y se caracterizan por tener capacidad hidrolítica frente a los antibióticos betalactámicos, lo que implica resistencia frente a penicilinas, cefalosporinas y aztreonam. También se asocian a resistencia a otros antibióticos. Existe alto riesgo de infección o colonización por productores de BLEE en pacientes con estancia hospitalaria prolongada o que han precisado dispositivos invasivos. El uso previo de antibióticos y la estancia en residencia de cuidados son también elementos de riesgo. Los programas de prevención deben centrarse en evitar la infección nosocomial. Resulta fundamental implantar una política restrictiva en el uso de antibióticos. La terapia de elección en infecciones graves se centra en carbapenémicos, aunque debe evitarse su uso indiscriminado. En la infección de tracto urinario bajo no complicada fosfomicina y nitrofurantoína son las mejores alternativas terapéuticas. Conclusión: Las cepas productoras de BLEE constituyen un verdadero problema de salud a nivel mundial. Las estrategias de prevención deben centrarse en la infección nosocomial, pero no debe olvidarse que cada vez es más frecuente la aparición de estos patógenos en infecciones comunitarias. Las decisiones terapéuticas deben basarse en el conocimiento de la distribución local de los microorganismos y sus patrones de resistencia

Context: Beta-lactamases are bacterial enzymes that protect microorganisms from the lethal effects of β-lactam antibiotics. The production of beta-lactamases is the most important mechanism of resistance to these antibiotics, especially in Gram-negative bacteria. Objective: Review the magnitude of the problem of extended-spectrum beta-lactamases (ESBL) in the urological setting and present the fundamental action guidelines on the issue, the main risk factors and the prevention strategies. Acquisition of evidence: A structured search strategy for patient, problem, intervention, comparison and result was conducted in the PubMed-Medline database to identify the most relevant studies related to the management of patients with urinary tract infection by ESBL-producing microorganisms. We also present a caseload analysis of our center on this issue. Summary of the evidence: ESBL are found in Enterobacteria, mainly Klebsiella sp. and Escherichia coli and are characterized by their hydrolytic ability compared with beta-lactam antibiotics, which entails resistance to penicillin, cephalosporin and aztreonam. They are also associated with resistance to other antibiotics. There is a high risk of infection and colonization by ESBL producers in patients with prolonged hospital stays or who required invasive devices. The prior use of antibiotics and stays in residential care are also risk factors. Prevention programs should focus on preventing nosocomial infection. It is essential that a restrictive policy on the use of antibiotics be implemented. The therapy of choice for severe infections is focused on carbapenems, although their indiscriminate use should be avoided. In uncomplicated lower urinary tract infections, fosfomycin and nitrofurantoin are the best treatment alternatives. Conclusion: ESBL-producing strains constitute a true global health problem. Prevention strategies should focus on nosocomial infection. We should not forget, however, that the appearance of these pathogens in community-acquired infections is increasingly frequent. Therapeutic decisions should be based on an understanding of the local distribution of microorganisms and their resistance patterns

Use of headspace sorptive extraction coupled to gas chromatography-mass spectrometry for the analysis of volatile polycyclic aromatic hydrocarbons in herbal infusions.

A solvent-free method is described for the determination of 10 volatile polycyclic aromatic hydrocarbons (PAHs), considered as priority pollutants by the EU, in different herbal infusions using headspace sorptive extraction (HSSE) and gas chromatography-mass spectrometry (GC-MS). The parameters affecting both the extraction and thermal desorption steps in the HSSE were optimized by means of Plackett-Burman designs. Ten millilitres of the herbal infusion was submitted to the HSSE preconcentration in the presence of salt for 4h at 88 °C. The use of d(10)-phenanthrene as internal standard not only improved the repeatability of the method but allowed quantification of the samples against external aqueous standards. Detection limits ranged between 11 and 26 ng L(-1).

Extended-spectrum beta-lactamases in urinary tract infections caused by Enterobacteria: understanding and guidelines for action.

CONTEXT: Beta-lactamases are bacterial enzymes that protect microorganisms from the lethal effects of ß-lactam antibiotics. The production of beta-lactamases is the most important mechanism of resistance to these antibiotics, especially in Gram-negative bacteria. OBJECTIVE: Review the magnitude of the problem of extended-spectrum beta-lactamases (ESBL) in the urological setting and present the fundamental action guidelines on the issue, the main risk factors and the prevention strategies. ACQUISITION OF EVIDENCE: A structured search strategy for patient, problem, intervention, comparison and result was conducted in the PubMed-Medline database to identify the most relevant studies related to the management of patients with urinary tract infection by ESBL-producing microorganisms. We also present a caseload analysis of our center on this issue. SUMMARY OF THE EVIDENCE: ESBL are found in Enterobacteria, mainly Klebsiella sp. and Escherichia coli and are characterized by their hydrolytic ability compared with beta-lactam antibiotics, which entails resistance to penicillin, cephalosporin and aztreonam. They are also associated with resistance to other antibiotics. There is a high risk of infection and colonization by ESBL producers in patients with prolonged hospital stays or who required invasive devices. The prior use of antibiotics and stays in residential care are also risk factors. Prevention programs should focus on preventing nosocomial infection. It is essential that a restrictive policy on the use of antibiotics be implemented. The therapy of choice for severe infections is focused on carbapenems, although their indiscriminate use should be avoided. In uncomplicated lower urinary tract infections, fosfomycin and nitrofurantoin are the best treatment alternatives. CONCLUSION: ESBL-producing strains constitute a true global health problem. Prevention strategies should focus on nosocomial infection. We should not forget, however, that the appearance of these pathogens in community-acquired infections is increasingly frequent. Therapeutic decisions should be based on an understanding of the local distribution of microorganisms and their resistance patterns.

Headspace sorptive extraction for the detection of combustion accelerants in fire debris.

A novel method for separation and identification of ignitable liquid residues in fire debris by gas chromatography and mass spectrometry is presented. Preconcentration of the analytes was carried out using the simple headspace sorptive extraction (HSSE) technique. Polydimethylsiloxane stir bars were used as the enrichment phase, and parameters affecting both the adsorption and desorption stages were carefully optimized. Extraction was carried out at 50°C for 1h. Stir bars were desorbed thermally in the GC injection port, thus avoiding the use of organic solvents. The results for five ignitable liquids, including gasoline and diesel fuel, using HSSE were compared with those obtained with a solid-phase microextraction method, with HSSE appearing as a more sensitive alternative.

Stir bar sorptive extraction with gas chromatography-mass spectrometry for the determination of resveratrol, piceatannol and oxyresveratrol isomers in wines.

A simple and highly sensitive procedure based on stir bar sorptive extraction coupled to gas chromatography-mass spectrometry by means of a thermal desorption unit (SBSE-TD-GC-MS) has been optimized for the determination of cis/trans isomers of resveratrol, piceatannol and oxyresveratrol in wine samples. Quantification of the cis-isomers was carried out by generating the standards from the corresponding trans-species once they had been preconcentrated on the SBSE extracting phase. The optimization of the acetylation derivatization, SBSE extraction and thermal desorption steps was investigated using Plackett-Burman designs, taking into account the high number of variables to be considered. The use of bisphenol F as internal standard allowed quantification of the samples against aqueous standards. Repeatability, expressed as relative standard deviation of 10 successive analyses was between 5% and 9%, confirming the high precision attained under the optimized conditions. Satisfactory recovery values of between 79% and 109% were obtained for spiked samples in the 0.2-1.0 µgL(-1) concentration range, depending on the compound. The main compound determined in the analyzed samples was trans-resveratrol, with concentrations in the range of 3-230 µgL(-1), depending on the type of wine.

Headspace sorptive extraction for the analysis of organotin compounds using thermal desorption and gas chromatography with mass spectrometry.

A method based on headspace sorptive extraction (HSSE) in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) has been developed for the simultaneous determination of six organotin compounds (OTCs), corresponding to mono- and di-substituted methyltin, butyltin and octyltin species. Several parameters affecting both the headspace extraction and thermal desorption steps were carefully optimized using multivariate designs. Analytes were derivatized by in situ ethylation with sodium tetraethylborate. The optimized method was applied to the analysis of water samples of different origins, as well as to checking the migration of the studied compounds from commercially available plastic containers to the adequate liquid simulant. Quantification was carried out against aqueous calibration curves using diphenyltin as internal standard, providing detection limits of between 1.7 and 7.0 ng(Sn) L(-1), depending on the compound, and repeatabilities lower than 10% in terms of relative standard deviation. The applicability of the method was assessed by means of recovery studies and satisfactory values for all compounds were attained. The release of OTCs from the tested packages to the liquid simulant was confirmed, concentrations as high as 2.4 µg(Sn) L(-1) being found for dioctyltin. Even though the proposed method was developed for organotin halides, its application to an organotin ester shows its suitability for determining these compounds in migration assays.

Stir bar sorptive extraction coupled to gas chromatography-mass spectrometry for the determination of bisphenols in canned beverages and filling liquids of canned vegetables.

This paper describes a method for the simultaneous determination of bisphenol A (BPA), bisphenol F (BPF), bisphenol Z (BPZ) and biphenol (BP), using stir bar sorptive extraction (SBSE) in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Several parameters affecting both extraction and thermal desorption of the SBSE stages were carefully optimized by multivariate designs. SBSE was performed with two derivatization procedures, in situ acetylation and in tube silylation, and the results were compared with those obtained when the analytes were not derivatized. The proposed method, determining the analytes as acyl derivatives, was applied to analyze commercially canned beverages, as well as the filling liquids of canned vegetables, providing detection limits of between 4.7 and 12.5 ng L⁻¹, depending on the compound. The intraday and interday precisions were lower than 6% in terms of relative standard deviation. Recovery studies at two concentration levels, 0.1 and 1 µg L⁻¹, were performed providing recoveries in the 86-122% range. The samples analyzed contained higher concentrations of BPA than of the other analytes.